A peripheral sensory and “supersensory” quantification, replacement, augmentation and analysis system is provided. More particularly, a data acquisition and transmission unit, a processing unit, and a receiving unit are provided. Some exemplary applications of the system include uses in healthcare, athletics, occupational health and safety and the military. Prominent healthcare uses include the management of peripheral neuropathy, lower extremity amputees and other rehabilitating patients.
Decreased or absent sensation resulting from peripheral neuropathy (or any other condition leading to inadequate sensation) leads to tremendous morbidity and poses a great challenge to the healthcare team caring for these patients. Sixty percent of peripheral neuropathy is secondary to Diabetes, with the remaining 40% being attributed to all other causes.
Nearly half of all diabetics will develop clinically significant peripheral neuropathy over the course of their lifetime; 25% are afflicted at any given point in time, and 7.5% of patients are symptomatic at the time of presentation. The vast majority of patients with peripheral neuropathy (of any cause) have a chronic, distal, symmetric polyneuropathy (i.e. decreased sensation in a stocking-and-glove distribution), affecting the nerves in a length-dependent fashion. Indeed, this prevalence data is thought to be skewed toward clinically relevant cases of peripheral neuropathy, and are likely somewhat underestimated. This prevalence data may be even further underestimated without the routine use of more sensitive methods of detection, including autonomic and quantitative sensory testing.
The prevalence of Diabetes in North America is 7%; nearly half of these patients ultimately have clinical courses complicated by peripheral neuropathy. The lifetime risk of a diabetic foot ulcer in these patients ranges from 15-25%, with a 2% annual incidence of ulceration. It has been estimated that 50% of all ulcers recur within 3 years, leading to further deleterious effects on patient quality of life and the health economy. Indeed, studies have shown that foot ulcers cause substantial emotional, physical, productivity, and financial losses. What is more, Diabetic Foot Syndrome (DFS) precedes 84% of all lower extremity amputations. In terms of the associated economic burden, the cost of treating a single diabetic foot ulcer (not factoring in recurrence) ranges from $18-$28,000 CDN, and approaches $35-50,000 CDN when the end result is amputation.
The consequences of peripheral neuropathy are manifold. First, this loss of protective sensation leads inadequate plantar feedback and therefore unchecked pressure distribution, leading to focal ischemia, pressure necrosis, ulceration, and then finally, infection and gangrene. Second, impaired sensation leads to balance dysfunction (“mal-equilibrioception”) and subsequent gait and mobility issues. Normal equilibrioception results from a coordination of visual, vestibular, and tactile/proprioceptive (predominantly plantar) inputs. While some variation exists between individuals, humans typically require two intact systems to achieve normal balance perception. In addition to the balance issues posed by decreased peripheral sensation, the lack of real-time feedback of when the plantar surface is on (and when it is elevated off of) the ground surface has further deleterious effects on mobility, often resulting in a slow, unsure and shuffling gait, and increased potential for falls.
These sensory, balance and gait concerns also apply to lower extremity amputees (users of prosthetic limbs) and other rehab sectors. In North America, it is estimated that 1 in 200 people are living with a lower extremity amputation, with these estimates expected to more than double by 2050. At present, this equates to over 1.7 million people. Indications for such amputation include severe ischemic disease of the lower extremity, traumatic mangling, tumor resection, infection, congenital limb deficiency, vascular compromise, and infection (often a consequence of severe pressure-induced diabetic ulceration). Following amputation, patients have problems with both care of the amputation stump, as well as their prosthesis. He or she must learn to apply, walk with, remove and care for the prosthesis; he or she must also monitor the stump skin for any pressure points, and ambulate on difficult terrain (in both light and dark) with inadequate sensory feedback from both the stump and the sole of the prosthesis. Resulting problems include stump damage, infection, further amputation and death, as well as issues with walking, balance and potential falls.